Bandura?s social cognitive construct "perceived self-efficacy" has been used widely to understand individual behavior as a function of domain-specific beliefs about personal capacities. Collective efficacy is the extension of the self-efficacy construct to organizations and groups; it refers to beliefs about collective capacities in specific domains. Our research is investigating the use of collective efficacy in understanding attitudes and behaviors of members of proximal residential communities with respect to issues like attachment, engagement, and sociality, specifically as modulated by use of the Internet and community networks. This paper describes our analysis of the structure and external validity of the collective efficacy construct.